The present invention relates to a very fast bistable logic device whose structure has been designed with a view to simplifying the internal organization of the bistable logic device and to improving its performance, especially in the very high frequencies between 5 and 10 GHz. It also relates to the application of this bistable logic device to a divide by 2 frequency divider operating from DC to a frequency of 10 GHz, this frequency divider being manufactured especially in the form of an integrated circuit on gallium arsenide. The development of microwave microelectronics, that is to say, microelectronics produced on new materials of the gallium arsenide type and on other derivatives of materials from the III-V and II-VI families, has required the parallel development of means of control and processing of the microwave signals. In fact, control and processing means or units in the form of integrated circuits working at maximum frequencies on the order of some hundreds of MHz are generally associated with a microwave system. For example, circuits on silicon are often associated with a microwave device on gallium arsenide in the technology called ECL. It is therefore necessary to interface the part of the system which works at microwave frequencies, generated by circuits on gallium arsenide, and the part of the system which works with circuits made on silicon, and consequently to make a frequency division to reduce GHz to MHz.
Without questioning the method of transposition of frequency according to which a given frequency is measured relative to local frequencies generated by very highly stable local oscillators, the present-day technical solutions are tending towards frequency division, which proves to be very advantageous on condition that the divider circuits:
operate at very high frequencies, of at least 1 GHz, that is to say at least twice the frequency of the highest performance present-day techniques;
operate in a high frequency band, so that there is no value in resorting to local reference oscillators; and
have their output frequency compatible with that of traditional integrated circuits, that is to say the division ratios are sufficiently large. The change from a frequency in GHz to a frequency in MHz is achieved by a succession of dividers of sufficient number.
In the field of division of periodic frequency, very advantageous results have been obtained in the 5 to 15 GHz band by means of structures using planar Gunn diodes. However, these dividers of periodic frequencies have the disadvantage of having a relatively narrow operating bandwidth, since .DELTA.f/f is approximately .perspectiveto.10%. The highest performance aperiodic frequency dividers work in a wider frequency band but need the application of two complementary signals, which is no disadvantage since the complementary signal is easy to generate.
Present day known frequency dividers work up to frequencies of 5.5 GHz: it is therefore necessary to bring about an advancement of the order of 2 at least for a new structure to offer advantages. It is this result which is covered by the frequency divider according to the invention.